This invention relates to methods and structures for attaching metal plates to members made of thermoplastic resin, and in one aspect to means for attaching a metal tape-cutting blade to a frame of a tape dispenser made of thermoplastic resin.
Many different inexpensive tape dispensers have been made to facilitate dispensing lengths of tape from a supply length of tape wrapped around a core.
Typically such dispensers have included a frame formed of thermoplastic resin, means on the frame for defining a path for the supply length of tape including means for rotatably mounting the tape core, and means along the path for defining a cutting edge transverse of the path adapted to transversely sever tape along the path when the tape and cutting edge are pressed against each other.
For many tapes dispensed from such dispensers (e.g., tapes with acetate backing layers), the means along the path for defining a tape cutting edge can be a serrated edge formed on the thermoplastic resin frame itself. Other tapes, however, have backing layers of materials (e.g., polypropylene) which are sufficiently difficult to cut that such serrated edges are not suitable and a metal plate having an edge adapted to cut the tape (called a tape-cutting blade herein) must be attached to the frame of the dispenser. Heretofore attaching such a tape-cutting blade has then presented certain problems. One prior art method of attaching such a blade includes forming spaced openings in the tape-cutting blade, molding appropriately spaced posts on the thermoplastic resin frame of the dispenser, positioning the posts through the openings in the tape-cutting blade, and then heat forming heads on the posts as by the use of ultrasonics to retain the cutting blade in place. While such a method provides good attachment, tape dispenser frames having such posts must have the metal tape-cutting blade attached to them even when they are to be used with tape that could be easily cut on an edge of the frame, because if the blade were not attached the posts would project into and obstruct the tape path.